(1) Field of the Invention
This invention relates to surface mount optoelectric semiconductor device package, particularly to a package with a focusing cup.
(2) Brief Description of the Related Art
In many optoelectric semiconductor packages, a focusing cup is used to focus the emitted light. The prior art structure and fabrication steps are shown in FIGS. 1-5. FIG. 1 shows two metal plates 111, 112 with through holes 121, 122. FIG. 2 shows a focusing cup 13 mounted over the two metal plates 111, 112. The metal plates 111, 112 are supported on an insulating substrate 14. The cup 13 has a reflecting wall 131 and is made of the same insulating glue as the substrate 14. The glue feeds through the through holes 121, 122 to attach the cup 13 to the substrate 14 with the metal plates 111, 112 sandwiched in between. The inner ends of these plates form the bottom of the focusing cup and serve to contact the electrodes of a diode (not shown). The substrate 14 has two grooves 141, 142 at the bottom corners of the substrate 14. FIG. 3 shows the folding of the outside ends of the two metal plates 111, 112 at the edges of the substrate 14 to form two bottom contacts 151, 152 for surface mounting the diode package to a motherboard. FIG. 4 shows a transparent 3-dimensional view of the diode package. This figure shows how the end of the metal plate 111 is folded to provide a bottom contact 151 for surface mounting, and how the end of the metal plate 112 is folded to provide a bottom contact 152 for surface mounting. FIG. 5 shows the bottom view of the structure with bottom contacts 151, 152.
The foregoing structure needs a thick substrate 14 for attaching the focusing cup 13 through holes 121, 122 in the metal plates 111, 112 to withstand the folding stress of the metal plates. The thick substrate 14 increases the height of the package and the cost. The through holes make it necessary for the bottom contacts to be wider than the through holes.
An object of the present invention is to reduce the height of a diode package with a focusing cup. Another object of this invention is to reduce the width of the package. Still another object of the present invention is to reduce the cost of such a package.
These objects are achieved by using preformed folded frames without using through holes. The focusing cup is directly glued to at least two folded metallic frames. Parts of the top surfaces of the folded metallic frame contacts the electrodes of a semiconductor device placed inside the cup. The bottoms of the metallic frames serve as the bottom contacts for surface mounting to a motherboard. The preformed metallic frames eliminate the folding stress in the prior art, and therefore can be made thinner than prior art. The elimination of the through holes can reduce the width of the package.